Asset model and CarrierWave uploader AssetUploader created.
Added file retrieval from assets. Assets themselves cannot yet be loaded as json or otherwise.
Assets now exposed as JSON via GET /assets and GET /assets/:id

Included the 'active_record_serializer' gem for managing serialization.
Using RABL or JBuilder for later permissioning or otherwise-nuanced forms of serialization but it was determined that this will not be necessary for a barebones drop-in asset server.